Classification of Bottle Defects

There are three classes of bottle defects. This topic was covered  when I attended a seminar at PTTC.
Class A. Critical defects which prevent the glass jar form performing their intended function of safely holding the product. It may cause danger to consumer.

  • Cracks anywhere in the jar.
  • Broken of chipped finish.
  • Contamination with dirt, insects, or any other foreign matter that cannot be easily removed by washing before filling.

Class B. Major defects that makes handling of jar difficult. Bottle durability is questionable.

  • Glass weight is below specified minimum.
  • Dimensions for height, diameter, volume or finish are outside tolerance.
  • Leaners (deviation form verticality) in excess of specified tolerances.

Class C. Minor Defects which adversely affect the appearance but not the function of the jar.

  • Uneven outer surface.
  • Slight off-color glass.
  • Rough mold lines.

Specific Glass Defects
bottle defects
1.Offset finish      2.Split finish      3.Bulged finish      4.Chipped finish      5.Checks under finish      6.Overpress      7.Corckage Check      8.Seam on side finish      9.Checked finish      10.Crizzled finish      11.Down finish      12.Out-of-round finish      13.Dirty finish      14.Threads not filled out      15.Tear under finish      16.Bent or crooked finish      17.Rough finish      18.Broken finish      19.Neck ring seam      20.Bent neck      21.Choked neck      22.Long neck      23.Hollow neck     24.Dirty neck      25.Pinched neck      26.Shoulder check      27.Thin shoulder      28.Sunken-shoulder      29.Hot checks   30.Pressure checks      31.Mold and Blank seams      32.Light sides      33.Bird Swing      34.Bruise checks      35.Letter checks      36.Flanged bottom      37.Light bottom      38.Heavy bottom      39.Rocker Bottom      40.Baffle Mark      41.Checked Bottom      42.Heel tap      43.Spikes      44.Washboard      45.Brush marks       46.Stones      47.Busters      48.Seeds      49.Cords      50.Black spots      51.Shear marks      52.Oil marks      53.Broken ware      54.Loading marks      55.Drag marks      56.Wrinkles or laps      57.Out-of-shape ware      58.Uneven distribution      59.Wavy appearance      60.Dirty appearance

Marvin is the lead chocolate maker of Ben and Lyn Chocolate Inc. Has strong background in food research and development. Occasionally conducts training and lectures. Lecturer of Cocoa Foundation of the Philippines. Do coaching and consultancy services on his free time.

15 Replies to “Classification of Bottle Defects”

    1. This article excerpt has a good explanation about bird swing. Hope it helps!
      The detection of the defect in glass containers known as a “bird swing” has been a continuing problem in the art. This defect is most prevalent when forming glass containers in the shape of flasks. The “bird swing” defect is a result of the two sides of the bottle contacting each other during the formation of the parison and prior to the blowing of the container into its final shape. As would be expected, when the two sides of the container touch, the hot, relatively “tacky” glass will fuse and as the container is expanded by air under pressure being introduced thereinto, the sides that have touched will move away from each other drawing a small thread of glass therebetween, thus forming what is termed a “bird swing”.

      1. Hi, could you tell me please where can I read about glass containers defects? Are there any books or articles about defects?
        Thank you

        1. I have never seen any books about it. Articles on-line are rare either. Try looking for Food Packaging Seminars – they can provide you with good knowledge and lot of resources.

  1. hi…i have an old beer bottle with a string of glass inside the bottle, at the bottom stringing from one side to the a u shape. deff a factory defect could of killed sumone!! please let me know if this sounds familiar to u as i am looking to sell this piece!! thank you

    1. Ashley, that defect is called a “birdswing” and it is a potentially deadly defect.
      Most modern manufacturing inspection equipment will cull out these and much less serious defects.
      Just out of curiosity,what is the manufacturing stamp or logo in the bottle? Its usually in the heel of the bottle.

      1. I have a Budwiser bottle circa 1977 with a bird swing. It is very noticeable and sags with some twisting on either end like it ran down the inside before cooling.

  2. Hello, I have a 16oz Budweiser bottle, with the twist off style cap.
    It’s from back in 1998 or 99.
    It has a very noticeable glass defect towards the top, just above where the bottle starts to curve in & reduce in size.
    I noticed the defect one night after work, as I sat down and was about to open it. Upon noticing it by feel, I visually inspected it and by eye, I could see how it was overlooked. It’s not real noticeable but if your looking for it, it’s very noticeable….if that makes sense. lol
    Anyways, shortly after noticing it and realizing I might have something of value….I called the 800 number for customer satisfaction at Anheuser Busch/Budweiser and described the bottle defect to the person I spoke with. Needless to say, they were very polite and VERY interested in having me send the bottle to them.
    In return for sending the bottle, I was told they’d issue me a voucher for a free case of beer!
    In an unsure way, agreed to send it back but was seriously thinking about keeping it….at the same time!
    They sent me a return kit, that has bubble wrap for the bottle with a box to return it in, lined with foam, with a cut out where the bottle would sit and also included a white Budweiser T-shirt…. Needless to say, I kept the bottle, shirt and return it….for the sake it might be worth something someday, to the right person.
    As a kid, I was always into collecting coins, stamps, arrowheads and whatever else I felt was collectable…only mentioning this because I’ve read about defects found on currency and postal stamps, plus many other thing’s, that have ended up being worth a fortune and realized this bottle might have significant value someday or might be of value now?
    Thanks for reading and feel free to contact me anytime.

    1. Hello! What a nice experience you have there!
      They want the defective Budweiser bottle back for three things
      1) to satisfy a possibly complaining customer.
      2) to see how the defect look like and formulate corrective action.
      3) keep it as collective item and possibly sell for hefty cost someday. The same thing you were thinking of.

  3. I recently dug a slug plate half pint milk bottle out of a cistern here in Cincinnati. When I wash washing the mud out of it my brush got snagged on something. When I noticed a spike or a tail. Lol
    I know the bottle is from the teens/20s and I know its approximately worth around 25 bucks. But with this bird cage/ spike located inside will it bring up the value anymore. There is no glass house markings on the base, just a few mold numbers. But if anyone has any information please let me know.
    Thank you

  4. Pingback: Help you know more about china glass bottles part 10: Glass manufacturing process’s five common defects | China Glass Bottles and Glass Containers and related packing materials Quality Control and inspection and Sourcing Service

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